I brought my iphone - planning to only to use the wifi, not for calling. I've discovered another use. In some museums, (I'm in Norway right now but have seen this in Sweden as well) displays have a QR code. When I scan the code, it gives me information, in English, about the display. The museums doing this offer free wifi, so if I had not already had the QR app, I could have downloaded it.
So glad I brought my iphone!!